You can use the Appearance panel and fills to fake the rounding of corners.

This method gives one a single or double rounded corner simply by clicking a Graphic Style. However, to change the color you have to alter 2 fills for each object in the Appearance Panel and to edit the rounding you may need to do a bit more tinkering with the appearance.

A workaround would be to select and cut the corner point, paste in front and use the Round corner effect. However to join the segment to the rest again, the appearance must be expanded which gives you the same result as if using the Round Any Corner script. The only advantage of the workaround is that you can keep the effect live for a time being before the final decision.